Does he sit close to you? Can he see you eating it? If not, great!! Share, and tell him it was delicious, and thank him like crazy for thinking of you. If he can see you.....thank him like crazy and tell him, you are going to bring it home to keep for your "free" day (wether you have one or not) and leave it in the freezer. (or toss it)
another thought, empty 1/3 of it into another bag and hide it in your purse....so it looks like you have eaten some of it.
Ive never been one for refusing something that has been given to me when the person specifically thought of me when they bought it. I dont want to hurt their feelings, so I will go out of my way to accomodate as best I can.
Kinda like the little boy(7 yrs old) across the street that made brownies, and specifically didnt put nuts in them (Im allergic) came out all proud with his home made brownie in his hand for me to try....then waited with those puppy dog eyes for me to eat it and tell him they were good. Well, I did
Whats a little brownie in the grand scheme of things.